“Not even a week after DuckTales: Remastered was removed from Steam, Grid 2 has followed it into the memory hole.”
The racing game had to be removed from the store for the same reason as the last game, couple of years ago : Expiring licenses, for its car model or either by the songs on the soundtrack.
Grid 2 was given away on the humble store in March, and the previous Grid was given for free before being removed.
If you already owned Grid 2, you will be able to download it.
The next game in the same serie called GRID will come out on October 11.